This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 8 |
| 5 | 39 |
| 6 | 240 |
| 7 | 1723 |
| 8 | 14165 |
| 9 | 130459 |
| 10 | 1331530 |
| 11 | 14894260 |
| 12 | 181259007 |
| 13 | 2383643794 |
| 14 | 33692516860 |
| 15 | 509433237073 |
| 16 | 8205927166103 |
| 17 | 140299345385359 |
| 18 | 2537807239717465 |
| 19 | 48423816128109123 |
| 20 | 972089365983087479 |
| 21 | 20481094574718083726 |
| 22 | 451904232651000126082 |